by
Kotz, John C.; Treichel, Paul M.; Townsend, John R.; Treichel, David A.

Answer

C

Work Step by Step

Neon is a noble gas, hence it has the bigger ionization energy.
Lithium's configuration would become a noble gas configuration by losing an electron, therefore it has the lowest I.E.
Carbon and silicon are in the same group so the one in a later period has a smaller I.E.